Spark plug



June 9, 1925. 1,541,042

' E. S. GORMACK SPARK PLUG Filed Oct. 6, 1922 Patented June 9, 1925.

EDWARD S. GORMACK, OF CHICAGO, ILLINOIS.

SPARK PLUG.

Application filed October 6, 1922. Serial No. 592,735.

To all whom it may concern:

Be it known that I, EDWARD S. GonMAoK, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Spark Plugs, of whlch the following is a specification.

This invention relates to spark plugs.

One object of my invention to prevent fouling of the plug by keeping the points at the spark gap clean and free of carbon and other deposits by housing or enclosing the electrodes in a metal shell which is heated by the explosions to burn all oil collected thereon before reaching said points and also to have the upper end of said shell above the upper end of the body so that the shell may be accessible from the outside of said body and be easily removed therefrom without unscrewing the body from the engine cylinder.

Another object of my invention is to have the insulating core terminate a suflicient distance above the lower end of the main electrode to be removed from the extreme heat at the spark gap, and also be removed from the active path of the explosive mixture when entering the shell and onissuing therefrom when ignited.

A. further object of my invention is to have the apertures in the shell arranged with one set below the lower end of the body so that no portion of the latter hinders free entrance of the mixture into the shell, and another set opening into the space between the shell and body so that flames of the explosive will be directed into said space to burn all oil collected therein.

The invention consists further in the matters hereinafter described and more particularly set forth in the appended claims.

In the accompanying drawings Fig. 1 is a front elevational view of a spark plug constructed in accordance with my invention;

Fig. 2 is a longitudinal vertical sect onal view through said plug;

Figs. 3 and 4 are transverse sectional views taken onlines 3-3 and 44, respectively, of Fig. 2;

Fig. 5 is a perspective view of the removable shell; 4

Fig. 6 is a vertical sectional view through the lower end of the shell, showing a double spark gap; and

Fig. 7 is a modified form of the structure to be hereinafter described.

A spark plug or my invention, as shown in the drawings, has a tubular body 1- made of metal and provided with a threaded lower end 2 for screwing intothe threaded opening provided therefor in the cylinder head of the engine with which the plug is used. Located in the body 1 is a shell 3 of relatively thin metal.

The upper end 4 of the with an enlarged recess to receive the enlarged upper end 5 f said shell 3, said upper end 4 has internal screw threads to re ccive, external screw threads on the upper end .5 of the shell 3, so that these parts may have removable connection with each other. Said recess provides an upwardly facing seat or shoulder 6 for the inwardly extending flange 7 provided on the shell at the base of its enlarged upper end 5. A gasket 8 is interposed between said parts, as shown in Fig. 2, to provide a leak proof joint.

Extending into the upper end of the shell 3 is a core or insulator 9. This is carried in a metal sleeve 10 provided with ex ternal screw threads to engage internal ones in the upper end 5 of said shell. The lower end of the sleeve 3 is bent inward to provide a base flange 11 seating against a gasket 12 on the flange 7 to form a leak proof joint between said parts when assembled, as shown in Fig. 2. The sleeve 10 has its up-' per end 13 bent over a shoulder on the core, which together with the flange 12 holds the sleeve on the core 9.

The upper end 5 of the shell 3 is above the like end 4 of the body 1, and the upper end 13 of the sleeve 10 is above the upper end of the shell 3. All of these parts are thus accessible from the outside of the body 1 and all made hexagonal or given such other shape to be engaged by a wrench or other tool when taking them apart or putting them together. This permits taking out the shell 3 for cleaning or repair without removing or loosening the body 1 from the engine cylinder.

The core 9 carries the main or central electrode 14. This is in the form of a straight rod extending below the core and into the shell 3. The lower end of the rod,

14 terminates short of a plug 15 screwed into the lower end of the shell 3 and closing body 1 is provided the same. Said plug 15 carries an up- 1 and mixture in the cylinder entering the shell for ignition by the spark at the gap. The upper set of apertures 17, 17 are above the lower end of the body 1 and open into the space 18 provided between the shell 3 and t e body 1. This space 18 allows the mixture to enter the shell 3 through the upper aperture 17 so that suflicient gas will be fired to explode'the charge in the cylinder. This upper set of apertures 17 facing the body 1 also directthe fiame produced by firing the mixture in the shell into the space 18 to burnany oil collected therein. The apertures being relatively small prevent oil carried by the mixture entering the shell to foul the points 14, 16 of the spark gap and thus the latter are kept clean and free of carbon deposit. Such oil as may collect on the outside of the shell 3 and in the space 18 is burnt through the heat of the explosions.

The body 1 and shell 3 are made long enough so that the space 18 will be of some length. This prevents oil reaching the gasket 6 and depositing there as carbon to bridge the space and produce a short circuit. It will be observed that the core 9 terminates adjacent the flange 7 and does not extend anywhere near the lower end of the rod 14 nor to any appreciable extent in the shell 3. This keeps the lower end of the core 9 removed from the explosions in the shell and pfevents burning and cracking of the core y the extreme heat produced at the spark gap. 4

As shown in the drawings, the core 9 extends above the sleeve 10 and is made of glass with a bore or chamber 19 in the same. The upper end of the electrode 14 ends in this chamber and is aligned with a terminal rod 20 extending into the chamber through its upper end. The rod 20 is carried by a cap 21 over the upper end of the core 9 and there a metal terminal bar 22 is provided for the attachment of a wire (not shown).

The spaced ends of the rods 14 and 20 provide an air gap to intensify the spark, and the core 9 being of glass allows the action of the plug to be observed.

Flg. 6 shows a modified form of construction. In addition to the point 16 on the screw plug 15, I provide another int 23. This is carried by the shell 3 and 1e in the below end, sai

also to permit ad ustment of the gap. By

the construction shown, two points 16- and 23 are provided. Should the lu 15 be left out, an operative cap woul still be had between the main electrode 14 and the point 23.

Fig. 7 shows another modification wherein the core is made in two parts 24, 25, the former being of an insulating material, as porcelain, the latter a tube of glass. The porcelain core 24 has an enlarged lower end 26 against which the sleeve nut 27 clamps to hold the part 24 in place. The glass tube 25 seats on this enlargement and is held in place by a set screw 28 carried by the nut 27 and entering a groove 29 in said tube. The upper end of the latter is closed by a cap 30 carrying a terminal screw 31 extending into the tube 25 and spaced at its lower end from the main electrode 32 to provide an air gap for intensifying purposes. The porcelain core 24 carries a nut 33 on the upper end of the electrode 32 for the attachment of a wire in case the glass tube 25 becomes broken or is not used.

While I have shown and described herein in detail a spark plug constructed in accord ance withmy invention, it is of course to be understood that the details of construction and arrangement of parts may be variously changed and modified without departing from the spirit and scope of my invention.

I claim as my invention:

1. A spark plug, comprising a tubular metal body. a metal shell extending into said body through its upper end and having removable connection therewith, said. shell being spaced from said body below its.

connection'therewith and having its lower end at the lower end of the body, said shell being provided adjacent its lower end with a double set of apertures, one set above the other, an insulating core carried by said shell at its upper end, and an electrode carried by said core and extending into said. shell to said apertures and surrounded by said shell.

2. A spark plug, comprising a tubular metal body, a metal shell extending into said body through its upper end and having removable connection therewith. said shell being spaced from said body below its connection therewith, said shellhaving its lower end closed and-extending below the lower end of said body, an insulating core extending into said shell through its upper end and carried thereby, and an electrode carried by said core and extending into said shell with its lower end terminating short of the closed lower end of said shell to provide a spark gap, said shell having a plurality of a ertures therein adjacent its lower apertures bein arranged in sets with ope set below the ower end of said body and the other set above said lower end and opening into the space between said shell and body.

3. A spark plug, comprising a tubular,

said body below its connection therewith, an insulating core extending into said shell through its upper end and carried thereby, an electrode carried by said core and extending into said shell toward its lower end, a

plug carrying a contact point closing the lower end of said shell, the lower end of the latter extending below the lower end of said body and there provided with a plurality of apertures arranged in sets above said plug, one set being below said body and the other set above the same and opening into the space between said shell and body.

4. A spark plug, comprising a tubular metal body, a metal shell extending into said body through its upper end and having removable connection t erewith, the upper end of said shell extending above said body to be reached from the outside thereof for removal, said shell extending below the for removal, said shell being spaced from lower end of said body and having its lower end closed, an insulating core extending into said shell through its upper end and carried thereby, an electrode carried b said core and extending into said shell, said electrode having its lower end terminating short of the closed end of said shell to provide a spark ga said core terminating at the connection t ereof .with said shell and leaving the electrode free for the reater portion of its length, said shell therein adjacent its lower end.

5. A spark plug, comprising a tubular metal body, a metal shell extending into said body through its u per end and havin removable connection therewith, said shel being spaced. from said body below its conhaving apertures nection therewith, an insulating core extending into said shell through its upper end and carried thereby, an electrode carried by said coreand extending into said shell, and a plug closing the lower end of ,said shell, said plu with said electrode a double spark gap, sai

shell having apertures therein adjacent said a I I I g iii testimony that I claim the foregoing as m invention,'I afiix my signature, 4th ay of October, A. D. 1922.

. EDWARD S.GORMACK.

and shell having points formin 

